1. Field of the Invention
This invention relates to in-line mixers and colloid mills and blades for such in-line mixers and colloid mills and more particularly to cutting blades for creating emulsions, suspensions, blends and dispersions.
2. Prior Art
In-line type mixers are precision machinery arranged to process pharmaceutical, biotechnology, cosmetic, chemical and food preparation to generate emulsions and dispersions thereof. In such machines, during the processing of such an emulsion or dispersion, rotating blades (sometimes called turbines) must impart a high shear to the product passing therethrough. Such emulsion or dispersion must be driven through the process smoothly and uniformly by proper rotors or blades therewithin.
It is an object of the present invention, to provide an optimum flow arrangement through the, processing chamber than that found in prior art.
It is a further object of the present invention, to provide a rotor blade arrangement having superior emulsifying characteristics.
The present invention relates to an in-line mixer to permit the operation of multiple mixing and milling heads arrayed in a series within a single drive section. A drive motor is arranged with an input shaft in-line with an input head. The drive head comprises a generally cylindrically shaped housing surrounding the output of the drive motor. The housing has a proximal end which comprises a flanged ring which can be attached to the drive motor. The housing has a clamp ring flange which is attached to a flange of an output head. The housing has a feed line comprising a port for forced flow release of pharmaceutical, biotechnological, cosmetic, chemical or food compounds therethrough.
In one embodiment, the drive shaft extends centrally through the housing having a blade and stator arrangement thereattached. A seal hub is positioned around the drive shaft adjacent to the clamp ring. The seal hub has a cone shaped truncated outer peripheral surface for passage of materials out of the emulsifying and dispersion chamber downstream thereof. In another embodiment, a separate drive shaft can be remote from the housing and driven by a remote motor attached, for example, by a drive belt or a coupling. In both embodiments, a proximal or first rotor blade arrangement is mated with the drive shaft distal of the hub seal. The drive shaft extends therefrom through a foraminous stator plate. The mid or second rotor blade is arranged distally of the first stator plate and a second foraminous stator plate is arranged distally of the second or midrotor blade arrangement. The mid or second rotor blade arrangement thus spins between the two foraminous stator plates which are stationary. A third rotor blade arrangement is disposed around the end of the drive shaft distally of the second foraminous stator plate. If desired, the blade and stator arrangement can be repeated as many times as is necessary for completion of the mixing and more than one rotor blade can be disposed before a foraminous stator. A locking cap is attached to the distalmost end of the drive shaft within the upstream end of the receiving chamber of the input head.
An input orifice is arranged within the input head to permit the emulsion and/or dispersion to be delivered therethrough. The foraminous stator plates in the preferred embodiment are disposed between the first and second rotor blade arrangement and between the second and third rotor blade arrangement. The plates have a plurality of passageways or openings which can be spaced on a plurality of circular paths therearound. The passageways are sized to permit the shear and turbulence required for the flow of compound therethrough while providing proper axial directionality thereof to the rotor blades rotating on either side thereof and also to provide the shear and turbulence required for the process.
Each rotor blade arrangement has at least two, and preferably three or more, equally spaced apart projections thereon. Each projection has a leading edge or blade, which in plan view, is arranged at an acute angle with respect to its adjacent frame edge and thereby form a throat for the flow of material. Each projection has a trailing edge of the blade which comprises a back surface thereof. The surface between the leading edge and the trailing edge of the blade on the projection is sloped to provide the force and directionality to compounds being emulsified or dispersed as the blade of the rotor rotates. The leading edge of the blade is arranged so it is not parallel or in alignment with the radius of rotation of the rotor blade. The leading edge of each blade defines an acute angle with respect to the frame edge. Thus, an acute angle is formed by the leading edge with respect to the side of the frame of the blade to provide an angled (non-radially oriented) sweeping and cutting action through the throat between adjacent projections across the passageways or openings in the face of the respective foraminous stator plates. By virtue of the acute angle. As the leading edge crosses the passageways of the stator plate, the compounds are imparted with a disorienting force to the components passing therethrough for increased dispersion an emulsification thereof. Preferably, one or more small vanes are disposed in the crotches between adjacent projections near the axis to enhance turbulence between the individual projections.
The invention thus comprises an in-line mixer apparatus for creating output emulsions and dispersions of pharmaceutical, biological, cosmetic, chemical and food compositions and includes a drive motor arranged around a support which has the motor shaft extending therefrom and can lead into a drive head. It further includes a seal hub arranged on the shaft and a plurality of alternating foraminous stator plates and rotors arranged about the shaft and a component inlet arranged through a distalmost end of the drive head. Each of the rotors can be a generally polygonal shaped member for improved compound flow therepast. Each of the rotors has an arrangement of at least two projections thereon, each of the projections having a leading blade edge and a trailing edge. A sloped surface is arranged between the leading edge and the trailing edge. Each of the rotors has a frame edge defining a side of the projection and each leading edge is arranged at an acute angle with respect to said frame edge. Each of the stator plates has an array of foramina which can comprise one or more annular, spaced-apart rows of openings therein for flow of emulsion and dispersion therethrough.